According to NFPA 70, what is the minimum working clearance required for enclosed electrical equipment...

NFPA 70 (NEC) Article 110.26(A)(1) establishes the depth of working space in front of electrical equipment. For systems 0–150 volts to ground, the minimum depth is 3 ft (36 in.); for 151–600 volts, the required depth is 3–4 ft depending on the condition (exposed live parts and grounded surfaces). In healthcare facilities, unless a more stringent “condition” applies, the baseline minimum clearance encountered for 600 V or less is 36 inches.